Ecological Evaluation Technical Guidance - State of New Jersey

Appendix G – Invertebrate Sampling MethodsMethods for sampling invertebrates include the use of artificial substrates, Surbersamplers, grab samplers and Rapid Bioassessment techniques. These are described below(modified text taken directly from the Field Sampling Procedures Manual (NJDEP,2005) and Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers(USEPA, 1999b).All benthic macroinvertebrates are preserved in 5 percent formalin (5 ml formalin/100 mlof water from which the organism was taken), with 95 percent ethanol, or isopropylalcohol. A Mason jar, or any glass or plastic wide mouth container can be used forbenthic macroinvertebrate samples.Artificial Substrates: (Hester-Dendy)These multi-plate samplers consist of eight large tempered plates separated by sevensmall plates, exposing one square foot of surface area. A hole is bored through the centerof each plate. Plates are placed alternatively on a galvanized eyebolt, threaded rod ornylon cord and secured. Samplers may have a brick attached to one end to anchor thesampler to the bottom for use in shallow streams, or they may be suspended fromanchored floats in lakes and deep rivers. Used throughout, artificial substrates provideconsistency of habitat to facilitate comparison among stations. Samplers are usuallyplaced at equal intervals across a stream. However, species colonization is greatlyaffected by current velocity. When conducting a survey, care should be taken to placesubstrates at locations having similar flow characteristics. Three samplers are routinelyplaced at each sample site, although more samples may be necessary to satisfy particularstatistical criteria. When using brick-anchored samplers, additional rocks are oftennecessary to secure the sampler upright. Care should be taken not to block the plates withthe rocks and thus limit colonization. Sampling devices should be placed asinconspicuously as possible because they are prone to removal by the public. They shouldbe secured with strong nylon line (not attached to the anchor line itself). In deeper waters,suspended samplers should be placed within the euphotic zone (i.e., shallower depthswhere light penetrates) usually less than 2 meters.The samplers should be removed after a six-week colonization period. Gently remove thesampler from the water so as not to dislodge the organisms, and immediately place thesampler in a plastic tub or bucket. Anchors attached to the substrate should not be placedin the tub until any organisms on the anchor are removed and discarded. Add a smallamount of water to the tub and wash the easily removable material from the plates. Thengently scrape the top and bottom of each plate into the tub, removing the plates ascleaned. Scalpel, spatula or soft toothbrushes are useful cleaning tools. Pour the sampleslurry through a US Standard No. 30 sieve. Additional water may be used to completelyclean the tub. Pass this through the sieve as previously described. Transfer the samplematerial from the sieve to the sample jars using forceps or a stream of water from a washbottle. Fill each jar no more than half full. Work directly over the tub so that any spilledmaterials can be recovered. Finally, inspect the tub for any remaining organisms andtransfer them to the sample jar(s). Water-resistant paper should be used for sample labelsand all information written with a soft lead pencil. Include sample (log) number, waterbody, station, sample number, sample device, and other pertinent information.Ecological Evaluation Technical Guidance Document 119Version 1.2 8/29/12